1. Field
This invention pertains in general to the field of digital dental design. More particularly the application relates to computer based virtual planning of dental restorations comprising dental prosthesis, as well as for methods of providing components for the dental restoration including a dental prosthesis, or components related to the dental prosthesis to be used during a dental restorative procedure, based on production data which is based on the virtual planning.
2. Description of the Related Art
In conventional dentistry, an impression of a region of interest in, or of the entire, oral cavity can be taken by means of an impression tray. From the impression a gypsum model of the lower jaw (mandibula) and the upper jaw (maxilla) can be cast by a dental technician for building a model of a desired dental restoration.
A wax appliance can be fit in the patient mouth for taking further measures and setting out certain desired landmarks in the oral cavity. Adjustments of the wax appliance can be made manually by the dentist when the wax appliance is inserted into the oral cavity of a patient. The wax appliance rests against the maxilla and/or mandibula, and can be used to mark, e.g., a central incisiory position, i.e., the dental midline or incisal line position between central incisor teeth, and a desired position of canines, as well as a desired smile line. The dentist can carve markings at the desired positions, when the wax appliance is installed in the patient. Further, a measure for the inclination of teeth in a dental restoration can be provided by carving the outer contour of the wax appliance that comes to rest against the lips.
Then, the dental technician receives the wax appliance in return. Based on the gypsum model, the wax appliance, which can be manually prepared in this manner, and using an articulator, the dental technician continues to manually prepare the dental restoration. A pre-denture can be prepared, e.g., as a dental wax-up, that corresponds to a model of the final restoration in the form of a denture. The pre-denture may for instance be put onto the soft-tissue of an edentulous jaw of the patient.
The dentist receives then this pre-denture in return, and the patient may need to be booked for another appointment, where the pre-denture is tried on by the patient and verified by the dentist. When the pre-denture is approved by the dentist, eventually with corrections, it is returned to the dental technician for preparing a final dental restoration.
However, this manual preparation using a wax appliance can have a number of disadvantages. For instance, it can be very time consuming, e.g., because the wax appliance may need to be sent back to the dental technician when the dentist has finished the patient specific adaptation. Furthermore, the precision of the final restoration may suffer. Many manual steps are a source of precision error, not at least due to the human factor. Consequences may be dire for the patient.
Hence, there is a need in some cases to provide a desired cost reduction in the preparation of dental prosthesis. The cost reduction could be achieved by reducing the number of manual steps.
Moreover, the range of possible products prepared by the dental technician may be limited. In addition, flexibility concerning adaptation and verification of dental restorations may be limited. When the dentist has carved too much material from the dental wax appliance, the process may need to be started all over again, and a new dental wax appliance may need to be prepared, the patient may need to be booked for multiple appointments, etc.
Known computer based methods, such as disclosed in U.S. Pat. No. 6,814,575 ('575), may still require such time consuming manual work. In '575 a denture is scanned that previously is prepared manually and has a fixed, manually determined teeth setup. Placement of dental implants is virtually planned, based on scan data of the patient's gum, jawbone and tissue structure, and of the manually prepared denture placed over the gum. The implants are positioned in jaw bone tissue based on a locked position of the scanned denture. Hence, the method disclosed in '575 is limited by fixed positions of the manually prepared denture. In FIG. 5 of '575 at position 39, false teeth of the reference denture are scanned. Based on this data, the implants' positions are chosen in the virtual planning. In FIG. 15 of '575 it is illustrated that an implant is adjusted, and the scanned and manually prepared denture (43, 44) is fixed. This computer based method thus lacks flexibility as it does not allow for a change of the teeth setup once the dental prosthesis is prepared, e.g., for taking into consideration a desired outcome of a dental restoration. Moreover, no data is provided to the technician manually preparing the denture, which is related to an appearance or position of facial tissue when the denture is placed over the gum. Thus, the final dental restoration, partly based on the denture, may not be optimal for the patient in terms of fit or aesthetics.
Hence, an improved method or system for virtually planning a dental prosthesis and/or for providing production data for a component related to the dental prosthesis based on the virtual planning can be advantageous and in particular allowing for increased flexibility, cost-effectiveness, versatility, patient comfort, and/or optimal calculation of dental prosthesis positions can be advantageous.